Background. Kidney cancer is a common malignancy in the U.S. with increasing incidence. While incurable at advanced stages with traditional therapies, renal cell carcinoma(RCC), the most prevalent form of kidney cancer, is responsive to immunotherapy. However, one of the most promising type of active tumor immunotherapy, Listeria-based vaccines, is not under study for RCC. Listeria-based vaccines are highly potent inducers of anti-tumor CTLs with significant preclinical success against cervical and breast cancer and ongoing clinical trials with promising results. The PI has expertise with Listeria-based vaccines and has developed a highly effective Listeria-based vaccine targeting CD105 (endoglin), a transmembrane glycoprotein involved in TGF-? signaling that is expressed by tumor-associated vascular endothelial cells. Listeria-based vaccination targeting CD105 resulted in dramatic reductions in metastatic disease and tumor vascularization in murine breast cancer. Interestingly, in RCC, CD105 is expressed both by the tumor cells and the tumor- associated vasculature. Targeting CD105 is, therefore, a uniquely ideal strategy for RCC immunotherapy. Objective/Hypothesis. The objective in this application is to determine the efficacy of targeting RCC tumoral and vascular-associated CD105 expression with a novel Listeria-based vaccine approach. Our central hypothesis is that induction of immune responses targeting tumoral and vasculature-associated CD105 expression with Listeria-based vaccines will be an effective therapeutic intervention to eradicate RCC tumors. In addition, we hypothesize that concurrent administration of the adjuvant, ISG15, will synergize with vaccination and augment CD105-specific cytolytic T cell (CTL)-mediated anti-tumor immunity. Specific Aims. (1) To determine the therapeutic efficacy of targeting kidney cancer tumoral and vasculature- associated CD105 with Listeria-based vaccines. (2) To determine the ability of the novel adjuvant, ISG15, to augment anti-tumor CTL responses and efficacy of Listeria-based vaccines targeting kidney cancer. Study Design. We will accomplish our aims through the use of in vivo murine tumor models and in vitro studies. We will utilize murine models of RCC to monitor tumor growth, disease progression, and tumor neovascularization after administration of Listeria-based vaccines targeting CD105 as the PI and Co-I have previously performed. In addition, we will vaccinate RCC tumor-bearing mice with Listeria-based vaccines targeting CD105 concurrent with delivery of the novel protein adjuvant, ISG15. We will then determine the synergistic efficacy of this strategy using methods and techniques previously performed by the PI. Impact. These studies are expected to have an important positive impact because they will provide a strong evidence-based proof of principle for the efficacy of Listeria-based vaccines to induce therapeutic immunity against RCC, thereby, offering solid justification for the continued development of Listeria-based vaccines as a novel treatment option for RCC patients with advanced disease.